Message

26class Message extends AbstractDataTransferObject27{28    public const KEY_ROLE = 'role';29    public const KEY_PARTS = 'parts';30    /**31     * @var MessageRoleEnum The role of the message sender.32     */33    protected MessageRoleEnum $role;34    /**35     * @var MessagePart[] The parts that make up this message.36     */37    protected array $parts;38    /**39     * Constructor.40     *41     * @since 0.1.042     *43     * @param MessageRoleEnum $role The role of the message sender.44     * @param MessagePart[] $parts The parts that make up this message.45     * @throws InvalidArgumentException If parts contain invalid content for the role.46     */47    public function __construct(MessageRoleEnum $role, array $parts)48    {49        $this->role = $role;50        $this->parts = $parts;51        $this->validateParts();52    }53    /**54     * Gets the role of the message sender.55     *56     * @since 0.1.057     *58     * @return MessageRoleEnum The role.59     */60    public function getRole(): MessageRoleEnum61    {62        return $this->role;63    }64    /**65     * Gets the message parts.66     *67     * @since 0.1.068     *69     * @return MessagePart[] The message parts.70     */71    public function getParts(): array72    {73        return $this->parts;74    }75    /**76     * Returns a new instance with the given part appended.77     *78     * @since 0.1.079     *80     * @param MessagePart $part The part to append.81     * @return Message A new instance with the part appended.82     * @throws InvalidArgumentException If the part is invalid for the role.83     */84    public function withPart(\WordPress\AiClient\Messages\DTO\MessagePart $part): \WordPress\AiClient\Messages\DTO\Message85    {86        $newParts = $this->parts;87        $newParts[] = $part;88        return new \WordPress\AiClient\Messages\DTO\Message($this->role, $newParts);89    }90    /**91     * Validates that the message parts are appropriate for the message role.92     *93     * @since 0.1.094     *95     * @return void96     * @throws InvalidArgumentException If validation fails.97     */98    private function validateParts(): void99    {100        foreach ($this->parts as $part) {101            $type = $part->getType();102            if ($this->role->isUser() && $type->isFunctionCall()) {103                throw new InvalidArgumentException('User messages cannot contain function calls.');104            }105            if ($this->role->isModel() && $type->isFunctionResponse()) {